Which links to use for T2?

Wow, so many answers... Thanks to everybody!

About links, after your tips I'm thinking now to use this type of links:

T2
web 2.0, cheap guest posting, SAPE. Eventually a little of article directories, edu and wiki.

T3
I leave for T3 other low-quality links (social bookmarks, blog commenting, forum links, profiles).

T1, as I have already written in the OP, is made of PBN (websites), web 2.0 (good quality) and some SAPE links.

Thanks again to all for your useful tips!!

For T2 Web 2.0, Guest post, And Social Bookmarking

Cheap PBNs and SAPE links for sure!

Tier 2 links- PBN links, Web 2.0, social bookmarks, diversified links.

For tier 2 you can use articles, profiles, url shortners, web 2.0, wiki, bookmarks.